1. Field of the Invention
The present invention relates to a recording apparatus and a control method thereof, and more particularly to a recording apparatus for recording moving image data after compressing the information volume, and a control method thereof.
2. Description of the Related Art
Heretofore, video cameras that take moving images and still images, and record these images to magnetic tape, memory card or the like together with sound are known. In recent years, video cameras (hereinafter, disk video cameras) that record images and sound to disk recording media such as DVD or hard disk drive (HDD) have also emerged.
Disk video cameras record captured moving image data to a disk recording medium after encoding the data using a high-efficiency coding scheme such as MPEG.
By adjusting quantization step width, the number of pixels and the like, many coding scheme including MPEG can change a compression ratio(%)=(pre-encoding data volume(d0)−encoded data volume(d1))/pre-encoding data volume(d0)*100.
The higher the compression ratio the smaller the data volume per unit time, although recorded picture quality deteriorates. On the other hand, a higher quality image can be recorded by reducing the compression ratio, although data volume also increases.
In view of this, disk video cameras are now provided with a plurality of recording modes at different picture qualities (compression ratios), and users can arbitrarily select one of recording modes (e.g., see Japanese Patent Laid-Open No. 2003-78743).
Users are thus able to appropriately switch the recording mode depending on the purpose of shooting, the duration of shooting or the like, enabling the limited recording capacity of disk media to be effectively used.
Typically, the remaining capacity on the recording medium and information about the status of use is displayed on an electronic viewfinder (EVF) screen or the like of the video camera. Video cameras with a plurality of recording modes at different compression ratios are able to increase the recordable duration if the remaining capacity on the recording medium is low, by switching from a high picture quality mode (low compression ratio recording mode) to a low picture quality mode (high compression ratio recording mode).
However, the user may conceivably forget to check the remaining capacity of the recording medium. It would not be unusual particularly for an inexperienced user who is not used to shooting with a video camera to become totally absorbed in following the subject, and not think to check the remaining capacity of the recording medium.
As a result, the user may first become aware that the recording medium has no more recording capacity when a message prompting him or her to change the recording medium is displayed. In this case, the user can either put in a new recording medium or else create recordable capacity by erasing recorded data.
However, deciding in a short time which video clips to erase when there are a large number of recorded video clips is extremely difficult. Shutter opportunities are missed as a result.